convection

• convection is the transfer of energy through gases or liquids
• when you heat up a liquid, the liquid near the heat source warms up faster
• the warmer liquid rises above its colder surroundings - like a hot air balloon does
• as the warm liquid rises, colder liquid takes its place
• the colder liquid is heated and when it starts to rise, colder liquid takes its place
• as the process continues, you end up with a circulation of fluid which results in the whole fluid being heated
• convection also occurs in ovens - hot air rises and cooler air falls in the same way